Cut-off valve for steam-engines.



No. 7|2,|97. Patented Oct. 28, I902.

c. A. MARRDER. OUT-OFF VALVE FOB STEAM ENGINES.

(Application filed Nov. 5, 1901.

, {No Model.)

2 Sheets-Sheet l,

INVENTOR WITNESSES ATTORNEY THE NORRIS PETERS c0. PHOTO-Una, WASHINGTON, D, c.

m.- 7|2,|97. Paten t ed och-2s; I902.

c. A. MARRDER. cur-urn VALVE FOR STEAM Ens-mas.

Application filed Nov. 5, 1901.)

(No Model.) 2 Sheets-Sheet 2.

INVENTOR v mo omw ATTORNEY- I m: "hams PETERS co FHGTO-L|THO., WASHINGTON, D. c.

-' :UNITED STATES PATENT OFFICE.

CHARLES A. MARRDER, OF NEW YORK, N. Y.

CUT-OFF VALVE FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 712,197, dated October 28, 1902.

Application filed November 5, 1901. Serial No. 81,237. (No model.)

To all whom it may concern-.-

Be it known that I, CHARLES A. MARRDER, a citizen of the United States, residing at New York, borough of Manhattan, and State of New York, have invented certain new and useful Improvements in Gut-0ff Valves for Steam-Engines, of which the following is a specification.

Thisinvention relates to a cut-off valve not only adapted for stationary steam-engines, but also and particularly adapted for locomotives and locomobiles, and the improvements have special reference to piston-valves with a lap and which are operated, as usual, by one eccentric that imparts the reciprocating motion.

With the cut-off piston-valves now generally in use and having the lap the inlet port or ports to the steam-cylinder will be closed too late and too slow only when the piston is near the end of its stroke, thus making a very unsatisfactory cut-off, while, on the other hand, the exhaust port or ports are closed too soon, thereby causing back pressure in the steam-cylinder, and consequently a defective engine.

The object of thepresent invention is to render cut-ofis for steam-engines more efiective and to save and conserve the steam, so that the his impressa is not uselessly wasted. By my invention I aim to produce the quick supply and cut off of steam during one stroke only of the piston-valve and to keep it cut off during the remainder of the same strokethat is, as regards one side of the piston only, as both sides act alternately, as usual, during the successive forward and backward strokes in admitting steam to the steam-cylinder.

My invention consists to these ends of certain features of construction and combinations of parts to be hereinafter described and then claimed.

In the accompanying drawings,which show two forms of my invention, Figure 1 is a 1ongitudinal section of a portion of a steam-cylinder and the valve-chest, showing myimproved cut-oif with valve closed. Fig. 2 is a transverse section on line 2 2, Fig. 1, the valve being open and somewhat to the right of the steam-ports as shown in Fig. 1. Fig.

3 is a side elevation of the piston valve and stem, showing a longitudinal section of the A the cylindrical valve-seat.

valve-rotating I device preferably employed. Fig. 4 is a transverse section on line 4: 4:, Fig. 3. Fig. 5 is a longitudinal central section of Fig. 6 is a section on line 6 6, Fig. 5. Fig. 7 is atransvers'e section of the valve and its seat after the valve has completed its stroke, the steam-ports being closed. Fig. 8 is a longitudinal section ofa cut-off for steam-engines, showing a modification. Fig. 9 is a transverse section of the cylindrical valve-seat and an end view of the valve, steam being admitted to the steam-cylinder. Fig. 10 is an inner view, and Fig. 11 an edge view, of an expansion-ring used in such modification; and Figs. 12 and 13 are respectively a longitudinal and a transverse section of the cylindrical valve-seat.

The steam-cylinder A supports the valvechest B, as usual, and the customary steamsupply channels C C, chest-ports G O, steamcylinder supply-channels D D, and intermediate exhaust ports d are provided. The steam-channels D Dare shown in Figs. 1 and 2 as continued in annular form at D around the cylindrical valve-seat and guide E, which is fitted, as usual, in and formsa part of the valve-chest. Opposite the respective annular channel portions D the valveseat E is provided with spaced ports d 01 arranged intwo annularseries. The pistonvalve F is turned to fit steam-tight yet slidingly in the cylindrical valve seat E, its valve-stem F being connected by a swiveljoint f with the reciprocating rod f, which is operated from the eccentric or other part of the valve motion. This swivel-joint permits a turning of the piston-valve during its reciprocation.

Referring more particularly to Figs. 1 to 7, the ends of the valve will be seen to be provided each with an annular series of projections g, separated by spaces g, so that lap portions are formed for the purpose hereinafter stated. These lap portions g correspond in number with the spaced ports d 01 as do also the recesses or spaces When the valve is being reciprocated, a properly-timed valve-rotating device causes the spaces g in the valve to temporarily register with the ports d d and the said ports to be quickly closed by the lap portions 9 as the valve is moving in one direction, while when moving in the opposite direction the lap portions keep the said ports closed. This action is due partly to the lap portions and intervening spaces and partly to a valve-rotating device, which may be of the form shown in Figs. 1 and 3 and a description of which follows.

A bracket I-I projects from one end of the valve-chest and carries a sleeve or housing H, in which is guided the valve-stem F, provided, preferably, with a cylindrical enlargement h, which guides the stem truly in the larger housing. A pin h projects laterally from one side of the valve-stem and is guided in a slot 71 extending lengthwise of the housing. Said slot has near the opposite ends on one side two cams b 72 facing each other, while on its opposite side and located at a point midway of the cams 72 h it has a double-acting cam 71 preferably formed as a semicircular lug. In operation steam is let into and after expansion out of the steamcylinder through the usual passages. Say the pistomvalve is making a return stroke in the direction of the arrow, Fig. 1. The steam at the receding end of the valve will pass through the inlet-ports d as soon as the spaces g communicate with the said portsand from thence into the steam-cylinder. When the valve has traveled a very short distance with full steam without lap, the inlet-ports 41 will be instantaneously closed, due to the quick partial rotation of the valve-stem and valve by the cam 72. which throws thelap portions g laterally across the said ports, so as to close them. The steam will now expand in the steam-cylinder and drive its piston a full stroke. On the forward stroke of the valve the same lap portionsg will keep the ports (1 closed, so that the full expansive energy of the steam let into the steam-cylinder may be utilized without permitting a surplus and unnecessary as well as uneffective amount of steam to enter upon the said stroke. After the lap portions have passed the ports d the intermediate cam it imparts a partial rotation to the valve reverse to that previously described, so as to bring the spaces g at the opposite end of the valve in position to establish communication between the said spaces and the inlet-ports d thereby admitting steam into the opposite end of the steam-cylinder. When by further but slight movement of the valve the pin h strikes the cam h a reverse turn is imparted to the valve, and the lap portions g are instantly thrown around to block and close the ports d During the first portion of the stroke in the direction of the arrow steam is let into the left-hand end of the valve-chest, and when the pin 72. strikes the cam 72 the valve is turned so as to bring the spaces 9 in position to be registered with the inlet-ports (Z and we have reached the point in this stroke from which we started. Cam 71 will therefore be seen to ordinarily functionate for admitting steam to the steam-cylinder and cams h 72 to ordinarily shut it off. By the described construction and operation the exhaust-ports (2 will close and open when the piston is at the end of its stroke, thus preventing back pressure in the cylinder.

In the modification shown in Figs. 8 to 13 the lap portions (indicated by I) are made upon an expansion-ring it, one of which is mounted at each end, of the piston-valve J, through which the stem J passes. The other parts indicated in these figures being substantially the same bear corresponding reference-let ters to corresponding parts in the other figures of the drawings. Expansion-ring 7c is split or divided at t' to form a skew-joint, and at the diametrically opposite side it is made preferably integral with a supporting-hub having a hole in line with the valve-stem, so that it may be placed thereon and secured by a nut Z. The expansion-rings for both ends of the valve when they are free spread or enlarge, and when they are in place they are somewhat compressed or reduced in diameter, so as to bear with yielding or spring pressure upon the valve-seat, the result being that they pack the valve and keep it steamtight by taking up wear. The lap portionsI and intervening spaces act the same as in the main form of the invention; but the valve is rotated differently by means of the device shown in Fig. 8. The radial pin on the valvestem enters a slot min the guide-housing M, which is stepped or formed zigzag, thereby producing a stepped cam. It will be apparent that at each stroke of the piston-valve it will receive two turns, the turn during one stroke being opposite to those of the other stroke, while in the other form of the invention two opposite turns are caused during each stroke.

I do not limit myself to the forms shown in the drawings, as it is evident that the same results may be produced by difierent constructions without departing from the scope of the invention, and it is also apparent that with some modification the device may be used for other engines.

What I claim as new and of myi'nvention 1s 1. In a cut-01f for steam-engines, thecombination of the valve-chest provided with spaced ports opening into the steam-cylinder, the reciprocating piston-valve provided with spaced or separated lap portions at each end, and a fixed camming device acting upon a portion of the valve for turning the valve during its reciprocation.

2. In a cut-0E for steam engines, the combination of the valve-chest, a piston-valve, an operating-rod, means for guiding and holding the rod in line with the axis of thevalve, and a swivel connection between the valve and operating-rod, substantially as described.

3. In a cut-off for steam-engines, the combination of the valve-chest, the reciprocating piston-valve provided with spaced lap portions at each end, and a fixed camming device for turning the valve twice during each stroke, for the purpose set forth.

4. In a cut-off for steam-engines, the combination of the valve-chest, a piston-valve, an operating-rod having a swivel connection with the valve-stern, and a fixed housingshaped guide for the stem, said guide being constructed with cam portions to engage a portion of the stem, for turning the valve.

5. In a cut-off for steam-engines, the combination of the valve-chest, a piston-valve provided with spaced lap portions, a stem, a pin or projection on said stem, fixed cams for engaging said projection, and means for reciprocating the valve.

6. The combination, with a piston-valve, of an operating-rod swiveled thereto and means for guiding and holding the rod in alinement with an axis of the valve.

7. In a cut-off for steam-engines,'the combination of the valve-chest, the reciprocating ber, 1901.

CHARLES A. MARRDER.

Witnesses:

EDWARD J. MURPHY, GEo. L. WHEELOCK. 

